NFC advice

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John Teague

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Oct 3, 2021, 11:11:38 PM10/3/21
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Hi R&D,

Im building a table-top game and exploring the idea of using NFC in some player pieces.

My thoughts so far for using NFC instead of RFID because 
  • NFC offers two-way communication + charging capabilities 
  • RFID is one-way + no charging - but I may be wrong in how I want to use it.
NFC communication is approx 10-50mm.

Context:
The player piece cannot be physically plugged into the games board, so cant use physical connections like sockets or rails.
Player piece is approx 30mm x 20mm x 10mm - but not yet set in stone yet.
Player piece has an LED that needs to flash when “triggered”.
The player piece itself doesnt need to save/store information, but will need a static ID to read for identifying it in the game.


My questions are:
1. Could I use something like this NTAG 213 NFC Tag on the player piece and connect the LED (with a triggering circuit?) to it so when the transmitter sends an NFC signal it would trigger the LED flashing.

2. Could the NFC signal (also) provide the power (NFC charging) to flash the LED - or be used in conjunction with a capacitor to store NFC charge and release when triggered - is it possible?

Any suggestions will be greatly appreciated!!

John.

Andrew Larkin

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Oct 3, 2021, 11:44:08 PM10/3/21
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How many game pieces?

How many board positions? 
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John Teague

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Oct 4, 2021, 12:07:13 AM10/4/21
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Hi Andrew,

For proof-of-concept, it would be a 4x4 grid using a coil matrix for the transmitter - one player piece.
For Prototyping, it would be a much larger 8x8 grid using coil matrix- 4 player pieces on the board.
Final board size would be approx 500mmx500mm (similar to monopoly board) - up to 8 player pieces at one time.

John.

Andrew Larkin

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Oct 4, 2021, 12:50:19 AM10/4/21
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Another approach would be to use a microcontroller like nRF52840 family powered by a button battery.

This has an NFC circuit that can be used to wake it up and then operate the LED.

You don't necessarily need to use NFC for communication as it also talks Bluetooth.

This means you might be able to just use 13.56MHz carrier switched to each coil in turn to solicit a BLE advertisement from a token at that location.

I'm using Raytac modules (10×15mm) with this chip. For your application one of the lower spec chips could work.

John Teague

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Oct 4, 2021, 1:08:52 AM10/4/21
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I considered BLE - the various ones I have lying around (including some nRF’s) might be a bit too big after adding button batteries and LED for the player pieces though… 

I’ll take another look into BLE as well - thanks for the suggestion.

John.

Patrick Barnes

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Oct 4, 2021, 6:28:08 AM10/4/21
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There are some pretty SMALL nRF modules out there...
image.png
8.55 x 3.25 x 0.85 mm, nRF module WITH antenna.
Who wants a bluetooth-enabled coffee bean? 😉

John Teague

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Oct 4, 2021, 7:55:37 PM10/4/21
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Crikey that IS small!!



Sent from my iPhone

On 4 Oct 2021, at 9:28 pm, Patrick Barnes <mrt...@gmail.com> wrote:



Madox

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Oct 5, 2021, 1:05:22 AM10/5/21
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I have some small nRF modules I have lying around too, let me know if you're interested :)

Not as small as the one Patrick linked, but probably 2-3x the size?

John Teague

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Oct 5, 2021, 11:42:24 PM10/5/21
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Cheers Madox :) 

That would be great! When the lockdowns lift shortly, we can catch up at the Space.

John.

Lewys Martin VK2EVA

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Oct 6, 2021, 10:30:10 PM10/6/21
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You can get nail stickers that have little LEDs in them that light on NFC readers... maybe this works for you ?

Thomas Squires

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Oct 6, 2021, 10:38:52 PM10/6/21
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Hi,

I hope to join the group after the lockdown restrictions ease.

Regards,

Tom

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Andrew Larkin

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Oct 6, 2021, 10:54:24 PM10/6/21
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Interesting.

These are likely to be just a coil and the LED, so no actual NFC/RFID function- just using inductive coupling to harvest energy.

You may be able to detect the presence of a piece on a square by inductive loading but won't be able to identify which piece.

Also, scanning the board for pieces will briefly illuminate each piece.

I could be wrong though.

John Teague

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Oct 6, 2021, 11:50:12 PM10/6/21
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I saw those nfc nail thingys and order a couple to see if I can make something from them :)

I like the direction of an attiny or ble mcu (I’m considering adding more than just a single led now) and have them powered by the nfc/coil and a cap?. I reckon I could poll each square and have the mcu trigger a response, maybe using a Hall effect sensor to work out the strongest magnetic  field to determine exact positioning?

Also trying to keep the costs per player piece as low as possible.

John
Sent from my iPhone

On 7 Oct 2021, at 1:54 pm, Andrew Larkin <and...@arcadius.com.au> wrote:

Interesting.

Will

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Oct 6, 2021, 11:53:57 PM10/6/21
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Hi all, do we know when the space is likely to be open next??

On Thu, 7 Oct 2021, 1:30 pm Lewys Martin VK2EVA, <countp...@gmail.com> wrote:
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Thomas Squires

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Oct 11, 2021, 9:54:37 PM10/11/21
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Hi I agree,

I would like to know when I can meet at the group for the first meeting back from covid lockdown and also my first meeting at the group in person? How much do I need to pay to be a member regularly? Also when does the group meet regularly? Once a week, on weekends? Or once a month on weekends?.

I guess there is a board for the club so a chairperson, treasurer, secretary etc. ?

Regards,

Tom.

Regards,

Tom

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Mitch Pommers

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Oct 13, 2021, 8:04:38 AM10/13/21
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I read through the Public Health Order and the roadmap after chatting with Gav about when the space would be open next.
Neither document makes explicit mention of makerspaces, which means going by something similar - we think we are similar to libraries.
The current Public Health Order lists Libraries as only being allowed to open for certain activities.
The City of Ryde Libraries are all closed or limited access until the 25th (date the 80% target changes should be applied on).
It looks like the 16+ 2nd dose coverage may hit 80% this week though, so the changed 80% restrictions may come in next week.

Erring on the side of caution when it comes to Public Health Orders, Pandemics, and Fines, it looks like the space will be open next on Tuesday the 19th (unless restrictions aren't changed by then, in which case it may be Tuesday the 26th)

Public Health Order if anyone wants some light bedtime reading: https://legislation.nsw.gov.au/information/covid19-legislation/general

@Tom: The space is normally open on Tuesday evenings and Saturdays from 11AM, with an email being sent to this list and rnd-announce when it is opened.
Membership information can be found on the website, with the first visit to the space being free: https://robodino.org/joining
Yes there is a board, but I don't know much about it.

MitchPommers

STEPHEN BUCK

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Oct 13, 2021, 4:22:43 PM10/13/21
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Thanks Mitch.  Looking fwd to getting back to work and catching up!

 

Stephen

Thomas Squires

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Oct 13, 2021, 6:33:57 PM10/13/21
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Ok I read your reply, thanks mitch.

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